With an image pickup apparatus such as a digital camera, strobe photographing has been conventionally carried out, which irradiates an object with a flash by using a strobe which is so-called a flash unit, to thereby photograph the object.
In the strobe photographing, generally, because of strobe light distribution characteristics, a flash is not uniformly distributed onto the object. Therefore, the object may look brighter at its center and darker at its periphery, or the object may look brighter as it is nearer, and darker as it is farther because it is unreachable by the flash.
Conventionally available techniques regarding strobe photographing are, for example, disclosed in Japanese Patent Application Laid-Open Nos. H11-331575, 2003-283922, and 2005-354167. Specifically, Japanese Patent Application Laid-Open No. H11-331575 discusses an image processing technique of obtaining, in portrait photographing with a wall set as a background, a distance of a person as a main object from information of the object, and correcting brightness based on light distribution characteristics in strobe photographing. Japanese Patent Application Laid-Open No. 2003-283922 discusses a technique of correcting an image based on light distribution characteristics including lens characteristics in strobe photographing. Japanese Patent Application Laid-Open No. 2005-354167 discusses a technique of correcting an image according to light distribution characteristics dependent on an object distance on the basis of pieces of distance measurement information of some places in strobe photographing.
However, the conventional techniques discussed in Japanese Patent Laid-Open Nos. H11-331575, 2003-283922, and 2005-354167 have had difficulties of removing local light distribution unevenness caused by the strobe (flash unit), from an image photographed by the strobe photographing.